This is another area in which different folks successfully use different “thinking” and techniques. I will discuss what and how I choose to “think” about the actions of the molten metal within the ceramic shell and the void of the piece to be cast. I like to “fill from the bottom” on large pieces while top filling works for smaller pieces and/or flat pieces. Below (A) is a piece set up for top filling while (B - D) are pieces set up for bottom fill. Top fill means that metal is going to go into the piece from the top, or near the cup, while bottom fill means the metal is going to start filling at the bottom of the piece and fill towards the top, towards the location that the molten metal is being poured.

Bottom filling causes less “splashing” and an even flow/fill. The metal is poured into the cup and flows down the sprue to the bottom of the piece, then into the piece as it starts.filling “from the bottom” in a easy, low turbulence flow. As in ANY casting, air displaced by the molten metal has to find a way out of the void being filled by the metal. Ceramic shell is a VERY porous casting material as air relatively easily can release right through the shell material, but even with this factor, it is recommended that some sort of air vents be allowed for in one form or another, to assure rapid and easy path for any air to get out of the void. I the “B” photo, there is a 1/2” piece of red wax coming from the top of the woman’s head and attaching to the pouring cup a few inches up from the cup/pouring sprue attachment for the main air relief (most of the times, these sort of vents are of 1/4” square wax but this one happened to also act as a major “attachment” of the wax piece to the entire setup, thus the use of the 1/2” wax rod. Most all feeder sprues will be square rather than round, as square rod lessens the tendency of the molten metal to swirl and form a vortex within the sprue, again the less turbulence the better.

There are “piss vents” from each finger on the woman’s hands, her nose and the Buffalo horn tips. These are made of a relatively soft wax that is simply “rolled” into a long cone shape. Once the shell is completed, the very tips of these vents is ground off (see inset within the Buffalo photo). The 3 vents showing are on the Bobcat Woman, 2 on the fur tuffs of the bobcat and a 3rd chin of the woman, just above the right “tuff” vent. All of these vents work very well.